Journal ArticleDOI
The FU Orionis Phenomenon
Lee Hartmann,Scott J. Kenyon +1 more
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In this article, the authors summarize the properties of FU Orionis variables and show how accretion disk models simply explain many peculiarities of these objects, and demonstrate that the FU Ori phenomenon is restricted to early phases of stellar evolution, probably with infall still occuring to the disk, which may help drive repetitive outbursts.Abstract:
▪ Abstract We summarize the properties of FU Orionis variables, and show how accretion disk models simply explain many peculiarities of these objects. FU Ori systems demonstrate that disk accretion in early stellar evolution is highly episodic, varying from ∼ 10−7 yr−1 in the low (T Tauri) state to 10−4 yr−1 in the high (FU Ori) state. This variability in mass accretion is matched by a corresponding variability in mass ejection, with mass loss rates reaching ∼ 10−1 of the mass accretion rates in outburst. It appears that the FU Ori phenomenon is restricted to early phases of stellar evolution, probably with infall still occuring to the disk, which may help drive repetitive outbursts. Thermal instabilities are a promising way to produce FU Ori disk outbursts, although many uncertainties remain in the theory; triggering by interactions with companion stars on eccentric orbits may also play a role.read more
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Journal ArticleDOI
Theory of Star Formation
TL;DR: In this paper, an overall theoretical framework and the observations that motivate it are outlined, outlining the key dynamical processes involved in star formation, including turbulence, magnetic fields, and self-gravity.
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Protoplanetary Disks and Their Evolution
Jonathan Williams,Lucas A. Cieza +1 more
TL;DR: A review of the outer parts, beyond 1 AU, of protoplanetary disks with a focus on recent IR and (sub)millimeter results can be found in this paper.
Journal ArticleDOI
Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A Grid of 200,000 YSO Model SEDs
TL;DR: In this article, a grid of radiation transfer models of axisymmetric young stellar objects (YSOs) is presented, covering a wide range of stellar masses (from 0.1 to 50 M) and evolutionary stages (from the early envelope infall stage to the late disk-only stage).
MonographDOI
Meteorites and the early solar system II
TL;DR: In this paper, the geologic diversity of asteroids and other rocky bodies of the solar system are displayed in the enormous variety of textures and mineralogies observed in meteorites, and the composition, chemistry, and mineralogy of primitive meteorites collectively provide evidence for a wide variety of chemical and physical processes.
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HERBIG-HARO FLOWS: Probes of Early Stellar Evolution
Bo Reipurth,John Bally +1 more
TL;DR: In this paper, the mass-ejection history of the newly born driving sources and their mass-accretion history is reconstructed using the Herbig-Haro (HH) objects.
References
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A powerful local shear instability in weakly magnetized disks. I - Linear analysis. II - Nonlinear evolution
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